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In aviation, instrument flight rules (IFR) is one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other is visual flight rules (VFR).
In aviation, the instrument landing system (ILS) is a precision radio navigation system that provides short-range guidance to aircraft to allow them to approach a runway at night or in bad weather. In its original form, it allows an aircraft to approach until it is 200 feet (61 m) over the ground, within a 1⁄2 mile (800 m) of the runway. At that point the runway should be visible to the pilot; if it is not, they perform a missed approach. Bringing the aircraft this close to the runway dramatically increases the range of weather conditions in which a safe landing can be made. Other versions of the system, or "categories", have further reduced the minimum altitudes, runway visual ranges (RVRs), and transmitter and monitoring configurations designed depending on the normal expected weather patterns and airport safety requirements.
A non-directional beacon (NDB) or non-directional radio beacon is a radio beacon which does not include inherent directional information. Radio beacons are radio transmitters at a known location, used as an aviation or marine navigational aid. NDB are in contrast to directional radio beacons and other navigational aids, such as low-frequency radio range, VHF omnidirectional range (VOR) and tactical air navigation system (TACAN).
Very High Frequency Omnidirectional Range Station (VOR) is a type of short-range radio navigation system for aircraft, enabling aircraft with a receiving unit to determine its position and stay on course by receiving radio signals transmitted by a network of fixed ground radio beacons. It uses frequencies in the very high frequency (VHF) band from 108.00 to 117.95 MHz. Developed in the United States beginning in 1937 and deployed by 1946, VOR became the standard air navigational system in the world, used by both commercial and general aviation, until supplanted by satellite navigation systems such as GPS in the early 21st century. As such, VOR stations are being gradually decommissioned. In 2000 there were about 3,000 VOR stations operating around the world, including 1,033 in the US, but by 2013 the number in the US had been reduced to 967. The United States is decommissioning approximately half of its VOR stations and other legacy navigation aids as part of a move to performance-based navigation, while still retaining a "Minimum Operational Network" of VOR stations as a backup to GPS. In 2015, the UK planned to reduce the number of stations from 44 to 19 by 2020.
In aviation, distance measuring equipment (DME) is a radio navigation technology that measures the slant range (distance) between an aircraft and a ground station by timing the propagation delay of radio signals in the frequency band between 960 and 1215 megahertz (MHz). Line-of-visibility between the aircraft and ground station is required. An interrogator (airborne) initiates an exchange by transmitting a pulse pair, on an assigned 'channel', to the transponder ground station. The channel assignment specifies the carrier frequency and the spacing between the pulses. After a known delay, the transponder replies by transmitting a pulse pair on a frequency that is offset from the interrogation frequency by 63 MHz and having specified separation.
An instrument landing system localizer, or simply localizer, is a system of horizontal guidance in the instrument landing system, which is used to guide aircraft along the axis of the runway.
In aviation, an instrument approach or instrument approach procedure (IAP) is a series of predetermined maneuvers for the orderly transfer of an aircraft operating under instrument flight rules from the beginning of the initial approach to a landing, or to a point from which a landing may be made visually. These approaches are approved in the European Union by EASA and the respective country authorities and in the United States by the FAA or the United States Department of Defense for the military. The ICAO defines an instrument approach as "a series of predetermined maneuvers by reference to flight instruments with specific protection from obstacles from the initial approach fix, or where applicable, from the beginning of a defined arrival route to a point from which a landing can be completed and thereafter, if landing is not completed, to a position at which holding or en route obstacle clearance criteria apply."
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A marker beacon is a particular type of VHF radio beacon used in aviation, usually in conjunction with an instrument landing system (ILS), to give pilots a means to determine position along an established route to a destination such as a runway.
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A transponder landing system (TLS) is an all-weather, precision landing system that uses existing airborne transponder and instrument landing system (ILS) equipment to create a precision approach at a location where an ILS would normally not be available.
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In aeronautics, the final approach is the last leg in an aircraft's approach to landing, when the aircraft is lined up with the runway and descending for landing. In aviation radio terminology, it is often shortened to "final".
Muscatine Municipal Airport five miles (8 km) southwest of Muscatine, in Muscatine County, Iowa, United States.
Inex-Adria Aviopromet Flight 450, JP 450, was an international charter flight from Tivat in the Socialist Federal Republic of Yugoslavia to Prague, Czechoslovakia which crashed in the Prague suburb of Suchdol on October 30, 1975, at 09:20 AM. The McDonnell Douglas DC-9-32 with 115 passengers and 5 crew on board descended, under Instrument Meteorological Conditions (IMC), below defined Minimum Descent Altitude (MDA) during the final approach to Prague Ruzyně Airport RWY 25, entered a gorge above Vltava river, and was unable to outclimb the rising terrain. 75 of the 120 occupants died during the crash itself while 4 others died later in hospital. The accident remains the worst aviation disaster on the Czech Republic soil.
Britannia Airways Flight 105 was an international tourist chartered flight from London Luton Airport for a flight to Ljubljana Brnik Airport. Passengers were primarily British, most of them going to their vacation in Yugoslavia. The flight was operated by Bristol 175 Britannia 102 aircraft, registration code G-ANBB. The aircraft took off from Luton at 21:10 hours GMT on August 31, 1966, with 110 passengers and 7 crew on board. After an uneventful en route flight, radar contact was lost at 00:47 hours local time on September 1 during the final approach to runway (RWY) 31. The aircraft struck trees in the woods by the village of Nasovče, 2.8 km south east of the RWY 31 threshold and 0.7 km north of the runway extended centreline, under Visual Meteorological Conditions (VMC). 98 of the 117 passengers and crew were killed in the accident.
On July 7, 2017, an Airbus A320-211 operating as Air Canada Flight 759 was nearly involved in an accident at San Francisco International Airport in San Mateo County, California, United States. The flight, which originated at Toronto Pearson International Airport, had been cleared by air traffic control to land on runway 28R and was on final approach to land on that runway; however, instead of lining up with the runway, the aircraft had lined up with the parallel taxiway, on which four fully loaded and fueled passenger airplanes were stopped awaiting takeoff clearance. The flight crew initiated a go-around prior to landing, after which it landed without further incident. The aircraft on the taxiway departed for their intended destinations without further incident. The subsequent investigation by the National Transportation Safety Board (NTSB) determined that the Air Canada airplane descended to 59 feet (18 m) above the ground before it began its climb, and that it missed colliding with one of the aircraft on the taxiway by 14 feet (4.3 m).
References
- Aeronautical Information Manual (AIM), published in the USA by Federal Aviation Administration
- ↑ AIM, 1-1-9c2
- ↑ As of September 2011, there are LDA approaches which have straight-in minima published despite the localizer being offset more than 30 degrees: e.g., "LDA/DME RWY 19" and "ROSSLYN LDA RWY 19" approaches to Runway 19 at DCA have 145 and 147 degrees respectively on their final approach course to the airport.
- ↑ This count reflects only clearly distinct approaches, i.e. if multiple LDA approach procedures to the same runway are available (all of which use the same localizer) they are counted as one. For instance, KSFO has "LDA/DME RWY 28R" and "LDA PRM RWY 28R (SIMULTANEOUS CLOSE PARALLEL)" approaches, which are essentially two different versions of the same approach, the latter one developed specifically for use in simultaneous parallel approaches to runways 28R (using LDA) and 28L (using ILS or RNAV). On the other hand, KDCA has two different LDA approaches to runway 19, which use different localizers, so they are both counted individually.
- ↑ "Digital – Terminal Procedures Publication (d-TPP)/Airport Diagrams". FAA . Retrieved 2016-06-06.
- ↑ "Instrument Flight Procedures Information Gateway". FAA . Retrieved 2016-06-06.
- ↑ Amendment 5 to DCA’s River Visual Runway 19 approach, June 5, 2015, by the FAA